The present invention relates to high definition television.
The competition among various industrial and academic institutions within the United States to win the approval of the Federal Communications Commission (FCC) for standardization of their respective versions of high definition television, or HDTV, has come to an end. In place of that competition and rivalry, a so-called Grand Alliance has come into being in which the former contestants are pooling their resources and expertise to arrive at a single standard that will be recommended to the FCC.
Most recently, the Grand Alliance has recommended that the FCC adopt as the modulation scheme for HDTV an approach that had been proposed by Zenith Corporation. The basic components of that modulation scheme are a concatenated coder driving a vestigial sideband (VSB) modulator. The concatenated coder, in particular, implements a particular Reed-Solomon code as the so-called "outer" code followed by a particular one-dimensional, four-state trellis coder as to so-called "inner" code. The Reed-Solomon code is the so-called (208,188) code. The one-dimensional trellis code is the code described, for example, in G. Ungerboeck, "Channel coding with multilevel/phase signals," IEEE Transactions on Information Theory, vol. IT-28, pp. 55-67, January 1982. The VSB modulator uses an eight-symbol, one-dimensional constellation, so that for each successive transmission symbol period, the concatenated coder, responsive to the source-coded HDTV signal bit stream, identifies to the modulator a particular one of the eight one-dimensional VSB symbols to be transmitted.